| M18: General | |||
| Date of first acceptance | July 1943 | Total acceptances | 2,507 |
| Manufacturers | Buick Motor Car Division of General Motors Corp. | Crew |
|
| M18: Dimensions | |||
| Combat weight | 37,557lbs 17,036kg |
Height over AAMG | 101" 257cm |
| Length without gun | 208" 528cm |
Gun overhang forward | 54" 140cm |
| Width overall | 113" 287cm |
Tread | 94.625" 240.35cm |
| Ground clearance | 14.25" 36.20cm |
Fire height | 73.8" 187cm |
| Turret ring diameter | 69" 175cm |
Ground pressure, zero penetration | 11.9psi .835kg/cm² |
| M18: Armament | |||||
| Type | Mount | Ammunition | Traverse | Max traverse rate | Elevation |
| 76mm Gun M1A1, M1A1C, or M1A2 | M1 in turret | 45 rounds (9 ready) |
360° (manual and hydraulic) |
24°/sec | +20° to -10° (manual) |
| .50cal M2HB MG | Concentric ring mount D60258 or D94428 on turret | 800 rounds | 360° (manual) |
-- | +85° to -13° (manual) |
| Aiming equipment | |||||
| Telescope M76C, M72C, or M70H; periscope M4 or M4A1 with telescope M47 or M47A2 for gunner | |||||
| M18: Armor | ||
| Assembly | ||
| Welding | ||
| Hull | ||
| Rolled homogeneous steel | ||
| Location | Thickness | Angle from vertical |
| Upper front | .5" 1.3cm |
64° |
| Upper middle front | .5" 1.3cm |
38° |
| Lower middle front | .5" 1.3cm |
24° |
| Lower front | .5" 1.3cm |
53° |
| Upper sides | .5" 1.3cm |
23° |
| Lower sides | .5" 1.3cm |
0° |
| Upper rear | .5" 1.3cm |
13° |
| Lower rear | .5" 1.3cm |
35° |
| Top | .31" .79cm |
90° |
| Floor | .19" .48cm |
90° |
| Turret | ||
| Rolled and cast homogeneous steel | ||
| Location | Thickness | Angle from vertical |
| Gun shield | .75" 1.9cm |
0° to 60° |
| Front (cast) | 1.0" 2.5cm |
23° |
| Sides | .5" 1.3cm |
20° |
| Rear | .5" 1.3cm |
9° |
| Top | Open | |
| M18: Automotive | |||||
| Engine | Continental R-975-C1 or -C4; 9 cylinder, 4 cycle, static radial, supercharged gasoline | ||||
| Horsepower | Net: 400@2,400rpm Gross: 460@2,400rpm |
Torque | Net: 940 ft-lb@1,700rpm Gross: 1,025 ft-lb@1,800rpm |
Fuel capacity | 165gal 625L |
| Transmission | 900T Torqmatic, 3 speeds forward, 1 reverse | ||||
| Steering | Controlled differential, steering levers | ||||
| Brakes | Mechanical, external contracting | ||||
| M18: Suspension | ||
| Type | Road wheels | Track return rollers |
| Torsion bar | 5 individually sprung dual/track | 4 dual/track |
| Drive sprockets | Idlers | Shock absorbers | 31-tooth front drive | Dual adjustable at rear of track | On first 2 and last 2 road wheels/track |
| M18: Track | |||||||
| T69 | |||||||
| Center guide, single pin, rubber bushed, steel, parallel grouser | |||||||
| Width | 12" (14.375" including track pins) 30cm (36.513cm including track pins) |
Pitch | 5.09" 12.9cm |
Shoes/track | 83 | Ground contact length | 116.5" 295.9cm |
| M18: Performance | |||
| Max level road speed | 50mph 80kph |
Max trench | 73.2" 186cm |
| Max grade | 60% | Angle of approach | 28° |
| Angle of departure | 26.5° | Max vertical obstacle | 36" 91cm |
| Min turning diameter | 66' 20m |
Max fording depth | 48" 120cm |
| Cruising range | ~100mi, roads ~160km, roads |
||
The M18 tank destroyer, known unofficially as Hellcat, was armed with the same 76mm gun series as the 76mm-gun medium tanks M4. The M18 was very fast, and its torsion bar suspension ensured a smooth ride over rough terrain. The drivers were provided with split hatches in the hull roof, and the turret was open-topped except for a small plate welded to the front right of the turret, which also supported the 76mm ammunition ready rack. The hull front featured a large service hatch for access to the vehicle's transmission and differential.
The 76mm guns themselves differ in the following ways: the M1A1C had the end of the barrel threaded for a muzzle brake, and the rifling of the M1A2 was one turn in 32 calibers versus one turn in forty for the other weapons. All M1A2s were equipped with muzzle brakes. The concentric ring mounts D60258 and D94478 differed in the construction of their supporting bearing fixed rings.
